Hole saw with tapered pilot bit

Abstract

The present invention provides a hole saw and pilot bit assembly. The pilot bit of the assembly has a portion which is devoid of flute and lobes and a portion including flutes and lobes. The portion including flutes and lobes further includes a portion which is tapered.

1 . A pilot bit comprising:
 a shank including a first portion having a proximal end and a distal end, a second portion having a proximal end and a distal end, said second portion extending from said distal end of said first portion, and a third portion having a proximal end and a tip, said third portion extending from said distal end of said second portion;   wherein said first portion is devoid of flutes and devoid of lobes;   wherein the outermost diameter of said second portion is consistent from said proximal end to said distal end thereof; and   wherein the outermost diameter of said third portion tapers inwardly along a length of the third portion from the proximal end to the tip.   
     
     
         2 . A pilot bit as defined in  claim 1 , wherein said first portion comprises approximately two-thirds the length of the pilot bit. 
     
     
         3 . A pilot bit as defined in  claim 1 , wherein said second and third portions extend approximately one-third the length of the pilot bit. 
     
     
         4 . A pilot bit as defined in  claim 1 , wherein the angle of taper is approximately three degrees. 
     
     
         5 . A hole saw and pilot bit combination comprising:
 a hole saw having a back plate, a skirt depending from said back plate, and a cutting edge at a distal end of said skirt; and   a pilot bit comprising; a shank including a first portion having a proximal end and a distal end, a second portion having a proximal end and a distal end, said second portion extending from said distal end of said first portion, and a third portion having a proximal end and a tip, said third portion extending from said distal end of said second portion;   wherein said first portion is devoid of flutes and devoid of lobes,   wherein the outermost diameter of said second portion is consistent from said proximal end to said distal end thereof; and   wherein the outermost diameter of said third portion tapers inwardly along a length of said third portion from the proximal end to the tip.   
     
     
         6 . The combination as defined in  claim 5 , wherein said first portion of said pilot bit extends approximately two-thirds the length of the pilot bit. 
     
     
         7 . The combination as defined in  claim 5 , wherein said second and third portions of said pilot bit extend approximately one-third the length of the pilot bit. 
     
     
         8 . The combination as defined in  claim 5 , wherein the angle of taper of said pilot bit is approximately three degrees. 
     
     
         9 . The combination as defined in  claim 5 , wherein the distal end of said first portion of said pilot bit extends distally beyond said cutting edge of said hole saw. 
     
     
         10 . The combination as defined in  claim 9 , wherein the distal end of said first portion of said pilot bit extends distally beyond said cutting edge of said hole saw by approximately 0.05 inches.